Doctors can implant his tiny sensor package developed by researchers at the Ecole Polytechnique Fédérale de Lausanne in Switzerland. A battery worn on a patch outside of the body gives it energy. When sensors detect chemical indicators of a heart attack, the system sends a warning to a Bluetooth-enabled device, such as a smartphone:
Often in the hours before a heart attack, fatigued or oxygen-starved muscle begins to break down, and fragments of a heart-specific smooth muscle protein, the troponin mentioned above, are dumped into the blood. If this can be detected before disruption of the heart rhythm, or the actual attack, lifesaving preemptive treatment can be initiated sooner. [...]
At the moment the device has a limited number of sensors, but there is no theoretical ceiling on this. Nor is there a limit to the kinds of enzymatic reactions or other detectors that could be used with those sensor channels. In the muscle breakdown scenario, for example, multiple products are in fact continuously generated in a tissue-specific manner which can give valuable information to athletes, and weekend enthusiasts alike. Ions and respiratory gases in the blood at different body locations can also be mapped.